The present invention relates to a method for controlling an agricultural machine system while it works a territory, with which a route is created for the machine system.
The route includes working tracks along which the machine system is driven to work the territory, and it includes headland tracks, along which the machine system is driven when it travels from one working track to the next working track. The machine system automatically carries out a sequence of headland working steps at the end of a working track and/or while a subsequent headland track is being driven along and/or at the beginning of a subsequent working track.
The present invention also relates to an automatic control system for controlling an agricultural machine system on a territory to be worked, with which a method of this type can be carried out.
Given that the performance of agricultural machine systems, i.e., working vehicles such as combine harvesters, forage harvesters or tractors with various attachments such as fertilizer spreaders, sowing machines, spraying devices, impellers, swathers, etc., has increased continually, the planning of the working steps has also grown in significance in recent years. For specific applications, harvesting in particular, the amount of time available for performing work is usually limited, usually due to the weather, and this time is often not used in an optimal manner due to lack of resource planning.
Precise resource planning is also important in order to attain the theoretically maximum possible performance of the machines in practical application. To reach this goal of optimal resource utilization, route planning systems and route planning methods were developed, which are used to determine an optimized route for working the territory, e.g., a certain field, for the particular machine system. The particular machine system can then be driven along this route—depending on the configuration of the machine system—either fully automatically, i.e., using automatic steering, semi-automatically, or simply manually with support from a suitable display device, which the driver uses to keep the vehicle on a virtual driving line.
Route planning systems of this type and automatic steering systems typically function using satellite-based navigation devices, e.g., GPS receivers (GPS=Global Positioning System). Various correction procedures are used to improve accuracy, such as DGPS (differential GPS) for a GPS method. An example of a route planning system of this type is described in EP 0 821 296 B1. As explained above, a planned route of this type typically includes the planned paths on the field to be worked, i.e., the individual “working tracks” on the field, as well as the driving courses for turning maneuvers in the headland areas, in order to travel from one working track to another working track that is usually directly adjacent thereto or is parallel thereto but offset at a distance.
The methods and route planning systems described above greatly simplify the work to be carried out by the operator of the agricultural machine system, since these devices and methods relieve him of the task of driving along long subpaths. However, the operator of the machine system must monitor and control a large number of functions during the turning operation, i.e., particularly when exiting one working track and entering a new working track. When exiting one working track, for example, the ground-working device usually must be raised, the vehicle must be shifted into a different gear, and the speed must be changed. When entering the new working track, the vehicle must be shifted into the correct gear, the speed must be adjusted, and the ground-working device must be lowered.
The working procedure—which often appears to be relatively simple when viewed from the outside—is actually composed of a large number of individual working steps. For example, an entire sequence of working steps to be carried out within a turning maneuver—referred to here as a “sequence of headland working steps”—can be broken down for a tractor with a drill combination of front packer, spinning body, harrow and drill machine into the following individual working steps:    1. Retract the front-mounted lifting means.    2. Retract the rear-mounted lifting means.    3. Turn off the P.T.O shaft.    4. Retract the track display.    5. Turn off the differential lock.    6. Deactivate the throttle.    7. Downshift.
Then, the actual turning procedure takes place. When the next working track is entered, the following individual working steps must be carried out:    1. Lower the rear-mounted lifting means.    2. Turn on the P.T.O shaft.    3. Activate the throttle.    4. Lower the front-mounted lifting means.    5. Lower the track display.    6. Upshift.    7. Turn on the differential lock.
This example alone shows that a turning procedure of this type requires a great deal of practice and the driver's full concentration. To relieve the driver of this task to the greatest extent possible, “headland management systems” (also referred to as “field-end management systems”) were developed and have been on the market for a few years. Using headland management systems of this type—some of which can also be retrofitted for tractors and other agricultural machine systems—sequences of headland working steps can be controlled automatically. To this end, various sequences of headland working steps can typically be “learned”. The operator switches the headland management system into a learning mode and carries out a turning maneuver, during which the individual working steps are registered and stored by the headland management system.
One problem with these systems, however, is that they are controlled solely in a time-dependent manner or—as with the automatic control system described in EP 1 380 202 B1—in a solely path-dependent manner. With purely time-dependent control, the sequence of working steps is “mirrored” in terms of time exactly the way it was recorded in the learning mode. This means the machine system must always perform the entire turning maneuver in the same amount of time. With path-dependent control, the stored operations are always carried out after the same distances that were covered when they were learned, regardless of whether the machine system moves at the same speed, or at a slower or faster speed than in the learning mode.
Both methods can be used effectively when the turning maneuvers between two working tracks are always the same, i.e., when the headland tracks to be driven are always the same. It cannot be assumed, however, that the optimal route for working a field means that the headland tracks between the individual working tracks are always the same. For example, it can be highly advantageous to choose a working strategy with which the sequence of working tracks to be traveled on the field does not require that the path length between the working tracks always be the same. If there are obstacles in the headland area, it may not be possible to travel along the headland track as planned.
Any considerable change to the headland track means that the sequences of headland working steps stored in the headland management system no longer match the headland track to be driven along and can therefore not be used without risking errors or, in the worst case, accidents. This means it is not possible to select an optimal route independently of the sequence of headland working steps that was stored and to travel along it fully automatically.